scholarly journals Assessment of the fatality rate and transmissibility taking account of undetected cases during an unprecedented COVID-19 surge in Taiwan

2021 ◽  
Author(s):  
Hsiang-Yu Yuan ◽  
M. Pear Hossain ◽  
Tzai-Hung Wen ◽  
Ming-Jiuh Wang
Keyword(s):  
Reproduction Number ◽  
Accurate Estimation ◽  
Fatality Rate ◽  
Hospital Capacity ◽  
Maximum Value ◽  
Daily Rate ◽  
Detection Ratio ◽  
Reporting Delays ◽  
The Difference ◽  
Case Number

Background During the COVID-19 outbreak in Taiwan between May 11 and June 20, 2021, the observed fatality rate (FR) was 5.3%, higher than the global average at 2.1%. The high number of reported deaths suggests that hospital capacity was insufficient. However, many unexplained deaths were subsequently identified as cases, indicating that there were a few undetected cases, hence resulting in a higher estimate of FR. Knowing the number of total infected cases can allow an accurate estimation of the fatality rate (FR) and effective reproduction number (Rt). Methods After adjusting for reporting delays, we estimated the number of undetected cases using reported deaths that were and were not previously detected. The daily FR and Rt were calculated using the number of total cases (i.e. including undetected cases). A logistic regression model was developed to predict the detection ratio among deaths using selected predictors from daily testing and tracing data. Results The estimated true daily case number at the peak of the outbreak on May 22 was 897, which was 24.3% higher than the reported number, but the difference became less than 4% on June 9 and afterward. After taking account of undetected cases, our estimated mean FR (4.7%) was still high but the daily rate showed a large decrease from 6.5% on May 19 to 2.8% on June 6. Rt reached a maximum value of 6.4 on May 11, compared to 6.0 estimated using the reported case number. The decreasing proportion of undetected cases was associated with the increases in the ratio of the number of tests conducted to reported cases, and the proportion of cases that are contact-traced before symptom onset. Conclusions Increasing testing capacity and tracing efficiency can lead to a reduction of hidden cases and hence improvement in epidemiological parameter estimation.

scholarly journals COVID-19 in comparison with other emerging viral diseases: risk of geographic spread via travel

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
A. Wilder-Smith
Keyword(s):  
Reproduction Number ◽  
Emerging Infectious Diseases ◽  
Case Fatality ◽  
The Elderly ◽  
Air Travel ◽  
Viral Diseases ◽  
Fatality Rate ◽  
The Past ◽  
Geographic Spread ◽  
Emerging Viral Diseases

Abstract Purpose of review The COVID-19 pandemic poses a major global health threat. The rapid spread was facilitated by air travel although rigorous travel bans and lockdowns were able to slow down the spread. How does COVID-19 compare with other emerging viral diseases of the past two decades? Recent findings Viral outbreaks differ in many ways, such as the individuals most at risk e.g. pregnant women for Zika and the elderly for COVID-19, their vectors of transmission, their fatality rate, and their transmissibility often measured as basic reproduction number. The risk of geographic spread via air travel differs significantly between emerging infectious diseases. Summary COVID-19 is not associated with the highest case fatality rate compared with other emerging viral diseases such as SARS and Ebola, but the combination of a high reproduction number, superspreading events and a globally immunologically naïve population has led to the highest global number of deaths in the past 20 decade compared to any other pandemic.

Magnetocrystalline Anisotropy and Twinning Stress of 10M and 2M Martensites in Ni-Mn-Ga System

2006 ◽  
Vol 512 ◽  
pp. 195-200 ◽  
Author(s):  
Nariaki Okamoto ◽  
Takashi Fukuda ◽  
Tomoyuki Kakeshita ◽  
Tetsuya Takeuchi
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Magnetocrystalline Anisotropy ◽  
Anisotropy Constant ◽  
The Other ◽  
Magnetic Shear ◽  
Maximum Value ◽  
Twinning Plane ◽  
Twinning Shear ◽  
The Difference

Ni2MnGa alloy with 10M martensite exhibits rearrangement of martensite variants (RMV) by magnetic field, but Ni2.14Mn0.92Ga0.94 with 2M martensite does not. In order to explain the difference, we measured uniaxial magnetocrystalline anisotropy constant Ku and the stress required for twinning plane movement τreq in these alloys. Concerning the former alloy, the maximum value of magnetic shear stress acting across twinning plane τmag, which is evaluated as |Ku| divided by twinning shear, becomes larger than τr eq. On the other hand, concerning the latter alloy, the maximum of τmag is only one-tenth of τreq at any temperature examined. Obviously, the relation, τmag> τr eq, is satisfied when RMV occurs by magnetic field and vice versa. In this martensite, the large twinning shear of 2M martensite is responsible for small τmag and large τreq.

scholarly journals Depth-Average Velocity from Spray Underwater Gliders

2018 ◽  
Vol 35 (8) ◽  
pp. 1665-1673 ◽  
Author(s):  
Daniel L. Rudnick ◽  
Jeffrey T. Sherman ◽  
Alexander P. Wu
Keyword(s):  
Average Velocity ◽  
Dead Reckoning ◽  
Water Velocity ◽  
Accurate Estimation ◽  
Underwater Glider ◽  
Underwater Gliders ◽  
Before And After ◽  
The Difference ◽  
Using Data ◽  
Acoustic Doppler Current Profilers

AbstractThe depth-average velocity is routinely calculated using data from underwater gliders. The calculation is a dead reckoning, where the difference between the glider’s velocity over ground and its velocity through water yields the water velocity averaged over the glider’s dive path. Given the accuracy of global positioning system navigation and the typical 3–6-h dive cycle, the accuracy of the depth-average velocity is overwhelmingly dependent on the accurate estimation of the glider’s velocity through water. The calculation of glider velocity through water for the Spray underwater glider is described. The accuracy of this calculation is addressed using a method similar to that used with shipboard acoustic Doppler current profilers, where water velocity is compared before and after turns to determine a gain to apply to glider velocity through water. Differences of this gain from an ideal value of one are used to evaluate accuracy. Sustained glider observations of several years off California and Palau consisted of missions involving repeated straight sections, producing hundreds of turns. The root-mean-square accuracy of depth-average velocity is estimated to be in the range of 0.01–0.02 m s−1, consistent with inferences from the early days of underwater glider design.

scholarly journals Predictors of COVID-19 Fatality: A Worldwide Analysis of the Pandemic over Time and in Latin America

2022 ◽  
Author(s):  
Dayana Rojas ◽  
Jorge Saavedra ◽  
Mariya Petrova ◽  
Yue Pan ◽  
José Szapocznik
Keyword(s):  
Latin America ◽  
Latin American ◽  
Strong Association ◽  
Case Fatality ◽  
Cross Sectional Study ◽  
Fatality Rate ◽  
Cross Sectional ◽  
The Difference ◽  
Latin American Countries ◽  
Risk Ratios

AbstractSARS-CoV-2 has infected over one hundred million people worldwide and has affected Latin America particularly severely in terms of both cases and deaths. This study aims to determine the association between SARS-CoV-2 testing and COVID-19 fatality rate worldwide over 8 months and to examine how this relationship differs between Latin America and all other countries. This cross-sectional study used March 2021 data from 169 countries. Multivariate regressions predicted COVID-19 fatality (outcome) from the number of SARS-CoV-2 tests (exposure), while controlling for other predictors. Results for March 2021 were compared to results from June 2020. Additionally, results for Latin America were also compared to all other countries except Latin American for March 2021. SARS-CoV-2 testing was associated with a significant decrease in COVID-19 fatality rate in both June 2020 and March 2021 (RR = 0.92; 95% CI 0.87–0.96 and RR = 0.86; 95% CI 0.74–1.00, respectively). SARS-CoV-2 testing was associated with a significant decrease in COVID-19 fatality rate in Latin American countries but not in all other countries (RR = 0.45; 95% CI 0.23–0.89 and RR = 0.95; 95% CI 0.82–1.11, respectively). However, the difference between the risk ratios for June 2020 and March 2021 and between the risk ratios for Latin America and all other countries were not statistically significant. Increased SARS-CoV-2 testing may be a significant predictor of lower COVID-19 case fatality rate, specifically in Latin American countries, due to the existence of a strong association, which may have driven the worldwide results.

Elevation gaps in fluvial sandbar deposition and their implications for paleodepth estimation

Geology ◽  
2020 ◽  
Vol 48 (7) ◽  
pp. 718-722
Author(s):  
Jason S. Alexander ◽  
Brandon J. McElroy ◽  
Snehalata Huzurbazar ◽  
Marissa L. Murr
Keyword(s):  
Large Data ◽  
Accurate Estimation ◽  
Systematic Bias ◽  
Flow Depth ◽  
Mean Flow ◽  
Data Set ◽  
Bed Elevation ◽  
The Difference ◽  
Base Elevation ◽  
Thickness Measurements

Abstract Accurate estimation of paleo–streamflow depth from outcrop is important for estimation of channel slopes, water discharges, sediment fluxes, and basin sizes of ancient river systems. Bar-scale inclined strata deposited from slipface avalanching on fluvial bar margins are assumed to be indicators of paleodepth insofar as their thickness approaches but does not exceed formative flow depths. We employed a unique, large data set from a prolonged bank-filling flood in the sandy, braided Missouri River (USA) to examine scaling between slipface height and measures of river depth during the flood. The analyses demonstrated that the most frequent slipface height observations underestimate study-reach mean flow depth at peak stage by a factor of 3, but maximum values are approximately equal to mean flow depth. At least 70% of the error is accounted for by the difference between slipface base elevation and mean bed elevation, while the difference between crest elevation and water surface accounts for ∼30%. Our analysis provides a scaling for bar-scale inclined strata formed by avalanching and suggests risk of systematic bias in paleodepth estimation if mean thickness measurements of these deposits are equated to mean bankfull depth.

scholarly journals The role of vegetation in the CO2 flux from a tropical urban neighbourhood

2013 ◽  
Vol 13 (20) ◽  
pp. 10185-10202 ◽  
Author(s):  
E. Velasco ◽  
M. Roth ◽  
S. H. Tan ◽  
M. Quak ◽  
S. D. A. Nabarro ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Anthropogenic Activities ◽  
Co2 Flux ◽  
Accurate Estimation ◽  
Urban Vegetation ◽  
Co2 Uptake ◽  
Total Contribution ◽  
The Difference ◽  
Residential Neighbourhood

Abstract. Urban surfaces are usually net sources of CO2. Vegetation can potentially have an important role in reducing the CO2 emitted by anthropogenic activities in cities, particularly when vegetation is extensive and/or evergreen. A direct and accurate estimation of carbon uptake by urban vegetation is difficult due to the particular characteristics of the urban ecosystem and high variability in tree distribution and species. Here, we investigate the role of urban vegetation in the CO2 flux from a residential neighbourhood in Singapore using two different approaches. CO2 fluxes measured directly by eddy covariance are compared with emissions estimated from emissions factors and activity data. The latter includes contributions from vehicular traffic, household combustion, soil respiration and human breathing. The difference between estimated emissions and measured fluxes should approximate the flux associated with the aboveground vegetation. In addition, a tree survey was conducted to estimate the annual CO2 sequestration using allometric equations and an alternative model of the metabolic theory of ecology for tropical forests. Palm trees, banana plants and turfgrass were also included in the survey with their annual CO2 uptake obtained from published growth rates. Both approaches agree within 2% and suggest that vegetation sequesters 8% of the total emitted CO2 in the residential neighbourhood studied. An uptake of 1.4 ton km−2 day−1 (510 ton km−2 yr−1) was estimated as the difference between assimilation by photosynthesis minus the aboveground biomass respiration during daytime (4.0 ton km−2 day−1) and release by plant respiration at night (2.6 ton km−2 day−1). However, when soil respiration is added to the daily aboveground flux, the biogenic component becomes a net source amounting to 4% of the total CO2 flux and represents the total contribution of urban vegetation to the carbon flux to the atmosphere.

scholarly journals Mismatch Based Diagnosis of PV Fields Relying on Monitored String Currents

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Pierluigi Guerriero ◽  
Luigi Piegari ◽  
Renato Rizzo ◽  
Santolo Daliento
Keyword(s):  
Energy Production ◽  
Figure Of Merit ◽  
Diagnostic Method ◽  
Medium Size ◽  
Time Interval ◽  
Instantaneous Power ◽  
Maximum Value ◽  
The Difference ◽  
Definition Of ◽  
Day By Day

This paper presents a DC side oriented diagnostic method for photovoltaic fields which operates on string currents previously supplied by an appropriate monitoring system. The relevance of the work relies on the definition of an effective and reliable day-by-day target for the power that every string of the field should have produced. The procedure is carried out by comparing the instantaneous power produced by all solar strings having the same orientation and by attributing, as producible power for all of them, the maximum value. As figure of merit, the difference between the maximum allowed energy production (evaluated as the integral of the power during a defined time interval) and the energy actually produced by the strings is defined. Such a definition accounts for both weather and irradiance conditions, without needing additional sensors. The reliability of the approach was experimentally verified by analyzing the performance of two medium size solar fields that were monitored over a period of four years. Results allowed quantifying energy losses attributable to underperforming solar strings and precisely locating their position in the field.

scholarly journals A Probabilistic Derivation of Heidke Skill Score

2014 ◽  
Vol 29 (1) ◽  
pp. 177-181 ◽  
Author(s):  
Otto Hyvärinen
Keyword(s):  
Skill Score ◽  
Base Rate ◽  
Harmonic Mean ◽  
Posterior Probabilities ◽  
Alternative Derivation ◽  
Prior Probabilities ◽  
Maximum Value ◽  
Heidke Skill Score ◽  
The Difference

Abstract An alternative derivation of Heidke skill score for 2 × 2 tables is presented, starting from the assumption that a categorical forecast is useful, if the probability of an occurrence of an event, given the forecast, is greater than the base rate of the event. A tentative measure of skill would then be the difference of these probabilities, normalized by the maximum value based on the base rate. For binary events, the Heidke skill score is then the harmonic mean of these differences for both the occurrence and the nonoccurrence of the event. This derivation differs from the usual derivation in that the concept of chance agreement is not used. It is Bayesian in nature with implied updating of prior probabilities to posterior probabilities.

Predation of Red Kangaroos, Macropus rufus, by the Dingo, Canis familiaris dingo (Blumenbach) in North-Western New South Wales

1981 ◽  
Vol 8 (2) ◽  
pp. 255 ◽  
Author(s):  
NC Shepherd
Keyword(s):  
New South ◽  
New South Wales ◽  
Pathological Finding ◽  
South Wales ◽  
Daily Rate ◽  
Rate Of Increase ◽  
Border Fence ◽  
Selection For ◽  
The Difference ◽  
North Western

Over 7 weeks a group of five dingoes killed 83 red kangaroos within 150 m of a watering point in north-western New South Wales. All except three of these kangaroos were juveniles. Detailed autopsies were performed on 17 of the dead kangaroos: primary predation was the only significant gross pathological finding; the dingoes had eaten portions from about half the kangaroos killed. The daily rate of killing was estimated to be about 0.38 kg prey per kg predator. The rate of killing and the selection for juvenile kangaroos suggested that dingoes could have a direct effect on kangaroo densities by limiting rate of increase. The significance of this finding is discussed with reference to the difference in abundance of kangaroos between the New South Wales and Queensland sides of the border fence.

Off-Axis Torsion Tests on Tubular Specimens of Steel

2001 ◽  
Vol 123 (3) ◽  
pp. 268-273 ◽  
Author(s):  
Takenobu Takeda ◽  
Zhongchun Chen
Keyword(s):  
Shear Stress ◽  
Yield Stress ◽  
Maximum Shear Stress ◽  
Torsion Test ◽  
Combined Loading ◽  
Anisotropic Hardening ◽  
Principal Stresses ◽  
Maximum Value ◽  
The Difference ◽  
Tubular Specimens

In order to analyze the anisotropic hardening behavior of metals, an off-axis torsion test by combined loading is developed. In this test, the maximum shear stress direction φ can be changed from 0 deg to 90 deg while the ratio of maximum and minimum principal stresses is kept at −1. With increasing angle φ, the yield stress of the torsional-prestrained steel decreases; the difference between the directions of the maximum shear stress and principal shear strain increment rises to a maximum value and then decreases. It is experimentally verified that anisotropy is more severe when a smaller offset strain is used in defining the yield stress.

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